Flexible container



Patented Apr. 25M, 1950 FLEXIBLE CONTAINER Marion M.A Cunningham, SouthBend, Ind., as-

signor to United States Rubber Company, New York, N. Y., a corporationof New Jersey i Application August 11, 1945', Serial N0. 610,289

My inventionk relates to liquid containers and more particularly to fuelcells of the coated flexible fabric type, one form of which isextensively used in carrying fuel in airplanes.

In the Gray and Zivi Patent No. 2,102,590,

issued December 2l, 1937, there is shown and described a liquidcontainer for aircraft in which the general dimensions of the confiningstructural elements are such that the Weight and impact forces of theliquid content ultimately react with the structural elements of theaircraft, rather than being resisted solely by the material of thecontainer.

In 'somercontainers it is desirable toluse reinforcing strips of thecharacter shown in a prior application, in which I am a joint applicant,Serial No. 573,128, led January 16, 1945, wherein the reinforcing stripsare shaped to closely conform to the corners or edges defined by theplane structural members. Also, in general, the supporting aircraftstructural members have greater flexibility in the areas intermediatetheir edges than at the edges. Accordingly, I have found that theadvantages of the Gray and Zivi construction can be obtained by makingthe edges of the panels of the container substantially conform to theshape defined by the structural elements of the plane and'by doming theareas of the panels intermediate the edges thereof.

The accompanying drawings illustrate a present preferred form of theinvention, in Which- Fig. 1 is a broken perspective View of thecontainer mounted on a forming frame and turned bottom side upwards;

Fig. 2 is a cross-sectional view of the container after removal of aform taken substantially along the section line 2--2 of Fig. l and Fig.3 is a cross-sectional view of a portion of an airplane wing, with acontainer mounted therein, the container being shown on the crosssectionline 3-3 of Fig. 1, and Without the form.

A liquid container preferably of the fuel cell type is provided withside Walls I, 2, 3 and il, a top wall 5 and a bottom wall 6, some ofwhich are united by reinforced seams i which are underlaid by flexiblereinforcing and stiffening strips 3. The seams and reinforcing stripsare described and claimed in said application Serial No. 573,128. In thepresent application the side walls and top and bottom walls are given anoutward or convex curvature such that when the container with the seams'l and the reinforcing strips 8 is inserted in a metal housing 9 formedin part by the structural elements l0, l I, and I2 of a metallic 3Claims. (Cl. 220-63) structure, which is illustrated in Fig. 3 as a por-55 tion of an airplane wing, the corners of the container fit snuglyinto the corners of the housing while the side walls and top and bottomwalls are free toengage and be supported by the housing S, therebyobtaining the advantages of the structures described in the Gray andZivi Patent No. 2,102,590.

In the manufacture of my improved container a form I4 of a solublecardboard construction is provided in which the side, top and bottomwalls are given an outward or convex curvature, or dome shape, withreference to the corners of the y container as is particularly 'shown inFig. 2. The

reinforcing strips 8 are placed along the desired edges of the form 'MProvisionis made in the form for a manhole mounting I 5 and pipe ttings,one of which is shown at i6. The coated fabric forming the side, top andbottom walls of the container is then stretched over and around theframe ill so that the fabric conforms to the shape of the frame. Theseams 'I are completed to unite them to the strips 8. Reinforcingstitching l1 may be employed. The edges of the fabric are trimmed to theresulting shape. As is shown in Fig. 2, the seams 1 lie within theproiection of the outwardly curved portions of the side, top and bottomwalls of the containers. The container is cured on the frame i4, whichis thereafter removed by a dissolving and washing operation which iswell known in the art.

As is shown in Fig. 3, when the container is mounted in the supportingstructure, the seams 1 snugly t into the corners or joints of thehousing 9 and the intermediate fabric of the side, top and bottom wallsor panels, which have the resultant domed shapes` are confined bv thestructural elements so that the weight of' their contents is transmittedto the structural elements without imposing extensive strains on thefabric. In such construction the joints between the sides of thesupporting construction resist distortion to a greater degree than theareas of the sides away from the joints, and such areas are sometimesexpanded or domed outwardly by the kinetic force of the fluid contents.Since the fabric panels of the exible container have been pre-domed,they are adapted to follow the outward movement of the walls of thesupporting structure without staining the fabric. Since the joints ofthe supporting construction are relatively free from distortion, thejoints of the flexible container closely fitting therein arecontinuously supported without making them oversize in respect to thesupporting joints, which oversize dimension would tend to cause them toleak as a result of the wrinkling.

Furthermore, with the above construction the advantage of the reinforcedcorners or seams is obtained Without sacrificing any of the spacevavailable in the supporting housing and Without excessively stressingthe fabric.

While havshoWn-land described at present preferred embodiment -ofmy"'in"vention, itis to be understood that the invention may be other-Wise embodied within the spirit of the invention and the scope of theappended claims.

Having thus described my invention, vv'lfiat claim and desire toprotectfbylLettes-Patetfis:

1. The combination of "ae'ell'i aving 'iiibl sides and a confiningstructure *having ""sid'es adapted to support the sides' of'lsaidfcell-.sides, the joints between said cell sides being preformed to t thecorresponding joints-*between said supporting structure sides, and thesides of 52.-'51-he-1cornbinaticnz of a `cell''for1f'cori-tamine liquidsand a supporting structure, saidis'up'porftcenters, preformed jointsuniting said flexible panels, and the outside length of said joints insaid cell being substantially equal to the inside length of thecorresponding joints in said sup- 5 porting structure.

3. The combination of a cell having ilexible sides and a confiningstructure having sides :adapted to support the``r s'izles` of said cellsides, A"the:junc'turerbetween the' sides of `said ncell being 10preformed and of a length substantially equal i 'rft'o the length of thecorresponding juncture of @thegs-idesof said supporting structure, andeach sidev oi said cell having a substantially greater 'fsuiifacefareathan the surface area of the correfl spcr'idin'gfside'4 lof Vthesupporting structure, which :Number Name Date `:1,1395g976 meDornier1..-.-- vJan. 31, 1933 @2341,450 `irdains .l- ..v May 19, 1936 $102,590Gray etal. 1 Dec. 21, 1937 1.230: 12,331-09'7 Watter v c Oct. 5, 1943FOREIGN -`#PATENTS Number' Country Date i 117,765 Australia May I28,-1942

